#include <iostream>
#include<vector>
#include<algorithm>
using namespace std;

int main () {
	pair<int, double>p1;
	cout << p1.first << "," << p1.second << endl;
	pair < string, int > p2("this", 20);
	cout << p2.first << "," << p2.second << endl;
	pair<int, int>p3(pair<char, char>('a', 'b'));
	cout << p3.first << "," << p3.second << endl;
	pair<int, string>p4 = make_pair(200, "hello");
	cout << p4.first << "," << p4.second << endl;
	return 0;
}